However, a tenant recently informed me he has a prescription for medical marijuana.I haven't been able to determine what each of our rights are (landlord & tenant) concerning this issue.

For instance, if I ever want to sell the home, I want to be able to note that there is not an implied easement or a prescriptive easement etc.

It's too dangerous otherwise.Mom knows and can have health care professional writing those prescriptions call you and give you definitive answer on medication.

An emotional support animal is not required to have any training or certification.As a landlord, you have the right to request documentation regarding the prescription of the animal but you cannot demand medical records or access to the medical personnel prescribing the animal. 

@Raymond GutierrezHi RaymondIn the city of Los Angeles building code, there is a prescriptive code section related to soils engineering requirements.

They also gave me the $600 a month in prescriptions I could no longer afford to cover my heart disease.

However there was a house here in 1989 it burnt down, the water lines have been there for over 10 years, so this is simply a prescriptive easement, not considering the possibility for an easement by necessity.

One came with a note from a counselor who "prescribed" the animal and told the mother she would turn her over to child protective services if she didn't fill the "prescription".  

This matter was discussed within a month, might search "property line" and "adverse possession" "prescriptive easements" are threads that touch on the matter.What you need is a proper survey from the seller, the seller must provide good title, the listing agent knows this.

@Joe Gore Hahaha......I love the people that sit around complaining the world is crumbling due to all the "potheads" ............while waiting on their prescriptions of Vicodin, Xanax and Ambien